The move was announced by Scottish first minister Alex Salmond in a letter to Ed Davey UK energy minister. There have been reports the UK Treasury is planning a 25% cut.

Earlier this month, the UK government announced it was delaying the decision on the level of subsidy wind power will receive through the RO.

Such decisions usually need to be announced before politicians in Parliament. The Department for Energy and Climate Change confirmed the delay, but would not give a reason.

Historically, Scotland's energy subsidies have been on a par with the rest of the UK. Salmond's decision ramps up the pressure on Davey to put forward his RO plans. Salmond said the delays were "wholly unnecessary" and jeopardise future investment in wind energy.

"DECC’s announcement this week to delay its ROC review decision has caused real anxiety to stakeholders and developers, especially in the light of recent press reports that the UK government is considering even lower onshore wind support levels than the 10% reduction proposed in the consultation."

Speaking about the decision, RenewableUK chief executive Maf Smith said: "We now urge the UK Government to publish its position and back onshore wind and the benefits it delivers to the UK economy. The economic evidence is clear to sources from the CBI to the Scottish Government, so there is no need for further delay."